This type of spring loaded weather stripping around the frame on the outside (so that the door pushes up against it) will go a long way towards reducing the drafts:

https://www.homedepot.com/p/Frost-King-1-5-in-x-84-in-Tall-White-Spring-Loaded-Door-Set-Weatherstrip-for-Entry-Doors-VAS82WH/315595908

Like many activities, it's hard to go wrong with a P100 respirator if you want to stay safe.

What about attaching a strong magnet on either side of where you want the hole to locate where to start drilling on top?

For much the same reason, we put in a momentary contact switch on the wall.

It's close enough that you can reach it while standing at the sink, but far enough that there's little to no chance of bumping it on accident and it would be awkward to reach the switch with one hand while your other hand is in the sink.

To make it easier to distinguish, it's also a different color than the rest of the switches in the kitchen (grey instead of white).

I've always been slightly tone-deaf and am in this for feel, not sound.

My experience with tung oil has been that it takes forever to cure, though.

Having just went through the process of doing a few custom wrist rests like this over the last few days, it's not worth sealing up until you're sure that you've gotten the ergonomics right.

Far better to work quickly & test it out for a few days first to see if the angle / height / depth are off at all.

My kids wound up with new wrist rests on their keyboards after I realized from an initial attempt that I really needed at least 4" of depth.